As Reltus quotes, we were worried about DK spike damage. With this change we feel that all of the tanks are pretty close in terms of surviving spikes, but at the moment DKs and Brewmasters require too little healing and warriors and druids require too much healing. Paladins are in a good place and serving as our target. Our solution to the rage tanks is probably going to be to give them more rage to use their defenses more. We haven't decided what to do with DK and monks yet. We're not considering major mechanics changes -- just numbers adjustments.

I posted recently in the large class balance theorycrafting thread that we have buffed the mitigation and rage generation of Guardian druids and Protection warriors. After some more analysis, we don't think DKs and monks needed additional nerfs to be on par with paladins, who were our target.